New Research Sheds Light on Cardiometabolic Risks in South Asian Populations
Two recently published studies provide data on the genetic and epidemiological factors associated with an elevated risk of cardiometabolic diseases in South Asian populations. One study identifies genetic variants linked to blood lipid metabolites, while the other reports on the earlier onset of risk factors for heart disease in U.S. South Asian adults.
Genetics of Lipid Metabolites in Asian Indians
A study published in PLOS Medicine investigated the genetic basis of blood lipid metabolites and their association with cardiovascular disease and type 2 diabetes in Asian Indian populations. The research was led by Dharambir Sanghera of the University of Oklahoma.
Methodology
- The study conducted a genome-wide association study (GWAS) on 516 lipid metabolites in blood samples from approximately 3,000 Punjabi Sikh individuals.
- Findings were validated using data from over 1 million Europeans and 15,000 individuals with South Asian ancestry.
Key Findings
- The analysis identified 236 genetic variant-metabolite pairs significantly associated with cardiovascular disease or type 2 diabetes.
- After multiple testing correction, 36 associations remained significant, of which 33 were novel and three were specific to the Asian Indian population.
- Two variants were highlighted: one in the CD45 gene linked to the metabolite LPC O-16:0 (a lysophosphatidylcholine), which was positively associated with type 2 diabetes risk; another in the FADS1/2 gene region linked to PC 38:4 (a glycerophospholipid), which was negatively associated with cardiovascular disease risk and may be specific to Indians.
"These findings could inform ancestry-specific medical interventions for cardiometabolic diseases, particularly in higher-risk populations like Asian Indians."
Implications
The findings suggest a role for immune system signaling in metabolic health. The researchers stated that these results could inform ancestry-specific medical interventions for cardiometabolic diseases, particularly in higher-risk populations like Asian Indians.
Limitations
- The study lacked an independent validation cohort of Asian Indians from India.
- Dietary patterns may affect blood lipid levels and influence ethnic differences.
- Only structurally characterized lipid metabolites were analyzed; unannotated peaks require further study.
Earlier Onset of Heart Disease Risk Factors in U.S. South Asian Adults
A study published in the Journal of the American Heart Association reports that South Asian adults in the U.S. are more likely to exhibit risk factors for atherosclerotic cardiovascular disease (ASCVD) by age 45 compared to white, Black, Chinese, or Hispanic adults of the same age.
Methodology
Researchers analyzed health data from approximately 2,700 adults aged 45–55 across two U.S. national studies: the Mediators of Atherosclerosis in South Asians Living in America (MASALA) Study and the Multi-Ethnic Study of Atherosclerosis (MESA). The MASALA Study collected data from South Asian participants (with ancestry from Bangladesh, India, Nepal, Pakistan, or Sri Lanka) between 2010–2013, with follow-ups in 2016–2018. MESA data for white, Black, Hispanic, and Chinese adults began initial checkups in 2000–2002 with follow-ups every two years until 2016–2018. The analysis focused on heart disease risk conditions including high blood pressure, prediabetes, and type 2 diabetes, alongside lifestyle behaviors such as diet quality, tobacco and alcohol use, and physical activity.
Key Findings
The study identified significant differences in heart disease risks, primarily driven by prediabetes, diabetes, and high blood pressure:
- South Asian Men (age 45): Had a higher prediabetes prevalence (30.7%) compared to white (3.9%), Chinese (12.6%), Black (10.4%), and Hispanic men (10.5%). They also showed a greater prevalence of high blood pressure (25.5%) compared to white (18.4%), Chinese (6.6%), and Hispanic men (10.1%). They had a higher prevalence of dyslipidemia (high cholesterol and/or triglycerides) than Black men (78.2% vs. 60.6%).
- South Asian Women (age 45): Had nearly double the prediabetes prevalence (17.6%) compared to white (5.7%), Chinese (8.2%), Black (9.0%), and Hispanic women (5.1%).
- Type 2 Diabetes (by age 55): Both South Asian men and women were at least twice as likely to develop type 2 diabetes compared to white adults of the same age.
- Lifestyle Factors: South Asian adults maintained higher diet quality, lower alcohol use, and comparable exercise habits compared to other groups.
"The earlier accumulation of heart disease risk factors among U.S. South Asian adults indicates a need for earlier screening, tailored prevention strategies, and prompt risk-factor management."
Implications and Recommendations
Senior study author Dr. Namratha Kandula noted that the earlier accumulation of heart disease risk factors among U.S. South Asian adults indicates a need for earlier screening, tailored prevention strategies, and prompt risk-factor management. Recommendations included checking blood pressure, glucose/A1c levels, and cholesterol in early adulthood. A 2023 American Heart Association statement suggested dietary modifications, such as increased whole-grain intake and selecting cooking oils lower in saturated fat, to help mitigate elevated ASCVD risk in this population.
Study Limitations
- The potential inaccuracy of self-reported behaviors.
- Participants in both studies were predominantly individuals with higher educational and socioeconomic status, potentially limiting generalizability.
- A decade gap existed between the initial baseline exams of MASALA (2010-2013) and MESA (2000-2002).